The invention relates to a shearing reinforcement for flat ceilings comprising several dowel strips arranged in a substantially radial position in the bearing area and each consisting of a dowel rail and a plurality of vertical, parallel dowels attached thereto at a distance from one another, whereby said dowels are provided with an elongated dowel shank and an enlarged dowel head on at least one end opposite said rail. The invention relates also to a dowel strip for such a shearing reinforcement.
Shearing reinforcements of this type are used in the transmission of vertical forces occurring in the bearing area of flat ceilings made of reinforced concrete or similar stressed concrete slabs (DE 27 27159 C3). The dowels, which are arranged perpendicular to the plane of the slab, absorb shearing forces that occur in the bearing area. The dowel shanks are thereby substantially stressed by a tensile load.
In addition to the especially favorable arrangement, as seen from a technical manufacturing viewpoint, of placing the dowels at equal distances apart along a dowel strip, it is also known to arrange the dowels at various distances from one another on the dowel strip. In particular, a closely spaced dowel configuration may be chosen for the highly stressed region in the immediate vicinity of the ceiling support of stay. A dowel spacing may be selected that is further apart in the zone away from the stay where there is less stress; however, exceeding the upper deviation value of a given dowel spacing is not permitted since an uneven shearing force distribution could possibly result thereby.
In practice, this leads to the fact that this shearing reinforcement is dimensioned according to stress conditions in the immediate vicinity of the stay and it is over-dimensioned at the region further away from the stay.
It is therefore the object of the invention to provide a shearing reinforcement of the type mentioned at the beginning so that an improved adaptation to the respective occurring stress is obtained.